Contact MEMS switches offer very low insertion loss, especially when building switch matrices with high throw counts (e.g. SP6T up to SP13T) and when operating at high frequencies (e.g. 2300 to 2700 MHz).
However, contact MEMS switches suffer from problems that affect their performance. For example, the following design constraints are difficult to achieve with MEMS switches: a maximum number of switching cycles over the lifetime of operation of at least 1e10 to 3e10 cycles; a fast switching time of less than 10 μs (this constraint requires very good anti-rebound control in MEMS); hot-switching capability (MEMS generally requires that the RF power is less than +0 dBm in order to avoid sparking and local heating that could degrade reliability); and tolerance for ESD (electrostatic discharge) events such as antenna discharge.
Thus, it is difficult to meet many design constraints using only MEMS switches.